References which are cited in the present disclosure are not necessarily prior art and therefore their citation does not constitute an admission that such references are prior art in any jurisdiction. All references cited are hereby incorporated by reference in their entirety.
The dried root of the plant Ilex pubescens Hook. Et Arn. is known as “Mao-Dong-Qing” and is commonly used in Traditional Chinese Medicine (TCM) for the treatment of cardiovascular diseases and hypercholestaemia. Previous chemical investigations have reported isolation of triterpene saponins1-6 and simple phenolics, i.e. 3,4-dihydroxyacetophenone, hydroquinone, scopoletin, esculetin, homovanillic acid, vomifoliol and glaberide from the roots and leaves of this plant7.
Pharmacological researchers have demonstrated that extracts of “Mao-Dong-Qing” could not only enlarge blood vessels, but also improve mini-circulation, lower blood pressure, inhibit platelet aggregation, prevent thrombus, reduce cardiac ischemia, decline the excitation of the cardiac conduction system and enhance the ability of anoxia resistance of body8. However, the exact compounds contributing to these effects have not been fully identified.
In regard to the inhibitory effect of “Mao-Dong-Qing” on anti-platelet activation and aggregation, it was reported that ilexonin A, a semisynthesized succinate of pentacyclic triterpene which is the aglycone of the saponins in “Mao-Dong-Qing”, could significantly inhibit platelet aggregation induced either by ADP (adenosine diphosphate) or AA (arachidonic acid) both in vivo and in vitro, and block 5-HT (5-hydroxytryptamine, serotonin) release by the platelets9. Other triterpenoids with antithrombotic activity isolated from Ilex pubescens have also been reported (Han et al, U.S. Pat. No. 4,987,125)17.
Despite these findings, the anti-platelet activity of Ilex pubescens extract has not been elucidated and may also be due to other hitherto unidentified compounds as well. It is therefore an object of the present invention to further isolate and identify biologically-active compounds from Ilex pubescens. 